I honestly don't get why people do it (unless every instance is a way to hide a stolen car identity). Are they so desperate to go to such lengths to save a few quid on road tax? Or is it so they don't have to MOT it?
I have a 1971 plate on my MPI, as it's being built up to look like an older car but it's still very much a 97 MPI, as per the logbook.